Vacuum discharge tube



Aug. 30, 1938. w. DLLENBACH VACUUM DISCHARGE TUBE 2 sheets-snez 1 FiledDec. 23, 1935 Aug. 30, 1938. w. DLLl-:NBACH 2,128,237

VACUUM DISCHARGE TUBE Filed Deo. 2S, 1935 2 sheets-sheet 2 Fig. 7

15 Z397 ZZ 24 Patented Aug. 30,-` 1938 UNITED STATES VACUUMv DISCHARGETUBE Walter Bllenbachlerlin-Charlottenburg, Germany, assignor toi JuliusPintsch Kommanditgesellschaft Application December 23, 1935, Serial No.55.885

In Germany December 24, 1934 19 Claims.

My invention relates to a vacuum discharge tube. More specifically itrelates to a vacuum discharge tube for stimulating ultra-high frequencyelectro-magnetic oscillations. .By the term stimulating I referparticularly to generating, amplifying or receiving such oscillations.

Generally speaking the essential parts of an ultra-short wave tube arethe electrode system, the frequency determining resonator combinedtherewith, and the load resistance, for example,

an aerial, connected with the resonator.

The present invention relates to a tube of the type in which theresonator is constructed as a plate condenser, and broadly resides indisposing U the electrodes substantially perpendicular to the condenserplates. The tube is preferably provided with an incandescent cathodeco-axial with the plate condenser, the cathode in turn being encompassedby other electrodes.

One object of my invention is to produce a superior ultra-short wavetube of the type in which the resonator is constructed as a platecondenser.

The invention has for another object the production of a tube whichprovides excellent stimulation while at the same time heat is readilyradiated oii" without difficulty. It is also my desire to eliminate thedefects in prior tubes.

Other objects and advantages of the invention will be more apparent fromthe following description and accompanying drawings, in which: Fig. l isa cross-section of a tube showing one example of my invention asconstructed for a braking field connection.

Fig. 2 is a cross section on the line 2-2 of Fig. 1.

Fig. 3 is a cross-section showing another embodiment of my invention asconstructed for a braking field connection.

Fig. 4 is a cross section on the line 4-4 of Fig. 3.

Fig. 5 is a cross-section of another embodiment of my invention asconstructed according to the magnetron principle.

Fig. 6 is a cross section on the line 6-6 of Fig. 5. Fig. 7 is across-section of an example of my invention as constructed according tothe magnetron principle and employing a grid.

Fig. 8 is a cross section on the line 8--8 of Fig. '1 Referring now toFigs. y1 and 2, it will be noted that a hairpin-shaped wire cathode I isprovided in the vertical axis of the arrangement. This cathode I isencompassed concentrically by a grid 2 the rods of which are parallel tothe axis and approximately the same length as the cath` ode itself.Surrounding the grid 2 and co-axial with the grid and the cathode is ahood-like solid wall electrode 3.

The reference numeral 4 indicates a circular plate of a plate condenser.At least the surface of this plate should be oi a good conductivematerial. The cathode I and the rods of the grid 2 are inserted in theplate 3 to be supported thereby.

The plate t is surrounded and enclosed or encompassed by the metal walls5 and 6. The metal wall 5 is provided with a central opening, l0 theedge of which is connected with the solid wall electrode 3. The solidwall electrode 3 and the wall 5, however, may be made integral. Themetal wall S is conductively connected atits edge with the metal wall 5as indicated at 6a. l5

At the axis of the metal wall 6 an opening 1 is provided for the aerial8. The aerial 8 is inserted in and supported by the plate 4. If theopening is closed oi by -means of a glass insulator 9, the metal walls 5and E together 20 with the solid wall electrode 3 will form a vacuumreceptacle. Y

The current leads for the cathode I may enter the arrangement at thepoint Ii), for example, through a glass-metal fusion, and then extend 25insulated into the interior of the plate 4 to the axis thereof at whichpoint they are connected with the cathode elements proper.

The lead to the grid 2 may enter the arrangement at the point Ii, and itis then conductively 30 connected with the plate il.

The reference numeral I2 indicates insulated supports, preferably ofceramic material. These supports retain the plate Il, and, consequently,the grid 2 in rigid concentric position relative 35 to the cathode I,the electrode 3, and the receptacle walls 5 and 6.

The arrangement operates in a braking eld connection in the followingmanner. The grid 2 receives a relatively high positive potentialwith 40respect to the cathode i. The solid wall, electrode 3 receives anegative potential in the vicinity of zero. The electrons emitted fromthe cathode l pass through partly between the rods of grid 2 into thespace between the grid 2 and the solid wall electrode 3, wherein theyreverse their direction under the influence of the braking field andthen, after a forward and backward movement, are caught up by the grid2. Now if a high fre- 5 quency field is maintained between the grid 2and the solid wall electrode 3, it will exert a controlling action onthe electrons which penetrate from the cathode into the braking ileldchamber or space between the grid and the electrode 3, 55

` whereby the electrons are capable of giving oi'f by the space betweentheplatel4 and the wall 5 which acts as a resonator so'that.-thereby, acurrent bulge and a potential node can at the margin of the plate 4. Apotential bulge occurs at the center, that is, in the vicinity of theaxis of the plate condenser. Connected to this potential bulge is thesolidwall electrode 3 servlng as the braking electrode, and the grid 2,so that between these two electrodes, as is known, there may arise ahigh frequency alternating field of maximum amplitude.

The function of the condenser space between the plate 4 and the wall 6is not only to form a short circuit capacity for the resonator spacebetween the plate 4 and the wall i. but also at the same time to receiveand maintain adjacent the base of the aerial 8 an alternating field oismall but suitable amplitude which acts to set the .The frequencydetermining system of the tube is really the condenser which is formedby the plate 4 and the wall 5, and it oscillates in its v basicoscillation. as stated, so that a potential node arises at its edge buta potential bulge at its center. The high frequency potential increasesfrom the edge of this condenser to the center continually. The currentfrom the edge to the center decreases continually. Ii neither thebraking electrode 3 nor the grid 2 were connected to this' condenser atthe center, thus in the vicinity of the axis, the diameter of thecondenser would be in simple ratio to the wave length, that is where adesignates the radius of the condenser, 'y the wave length, and thenumber 2.405 the first zero point of the Bessel function of zero order.This formula is not strictlyfulillled since the cylindrical condenserformed by the grid 2 and the braking electrode 3, which is connectedwith the plate condenser 4, 5, has an additional capacity which resultsin lowering the frequency and thus in increasing the wave length.

The cylindrical condenser formed by the grid 2 and the electrode 3 may,of course, be shorter, especially considerably shorter than 1/4 of thewave length, so that it may be considered as an aperiodic structureconnected to the resonator space between the members 4 and 5. l

'I'he aerial 8 may be tuned in any known manner, or, to moderate themost favorable load of the generator, may be more or less tuned out withrespect to resonance. The aerial extends above the plate formed by thewall 8 like a Marconi aerial over the earths surface.

The principal advantage of the present arrangement with respect toprevious arrangements consists chieily in that the cathode I as well asthe grid 2, which form the parts which become the hottest. areheat-conductively, con nected with a good conducting metal mass 4 so asto provide excellent cooling for the parts subf Jected tothe greatestthermal strains. l

Moreover, a plate condenser such as described possesses an advantageover a concentric Lecher system, for example. in that the dimensions aregreater so that when short wave lengths are to be produced the tube willpossess sumcient dimensions to permit their production. y Finally theplate condenser of the present in vention is of advantage in that, ifthe space between the plate 4 and the wall 5 is not too small, theso-called y-wheel moment of the resonator, as compared with anoscillatory circuit consisting of a concentric capacity C and aconcentrated self-induction L of the magnitude is relatively large. Thiscondition is very iavorable for the production of stable oscillations.

In the` embodiment disclosed in Figs. 3 and 4, the reference numeral Iagain represents the cathode, 2 the grid disposed around it. and 3 thedamping orvbraking electrode. The embodiment diners from that disclosedin Figs. 1 and 2 in that the connections of the grid and the solid wallelectrode are interchanged. That is, the grid 2 is connected to an outerwall 5, and the electrode 3, on the contrary, is connected to the plate4 disposed within the tube.` 'Ihe advantage of this arrangement is thatthe cooling of the grid 2, at which the main energy is realized, isstill better, since the grid 2 is connected with the plate I and thelatter is in direct communication with the atmosphere.

'I'he operation of this embodiment of the invention is the same as thatof the embodiment disclosed in Figs. l and 2. `The plate condenserformed by the plate 4 and the wall B together with the cylindricalcondenser formed by the grid 2 and the electrode 3 (which isconsiderably shorter than 1/4 of a wave length), serve as a resonator.Here again, a potential node line is formed at the margin ofthe platecondenser. when the condenser formed by the elements 4 and 6 are given arelatively small wave resistance with respect to the resonator spacelimited by the elements 4 and 5. The condenser space between 4 and 6thus serves on the one hand as a short circuit capacity for theformation of a. potential node at the margin of the condenser, and onthe other hand as a high frequency lead to which the aerial 84 isconnected in a relatively loose fashion. 'I'he aerial 3 is a directprolongation of the cylinder 3 which serves as the braking electrode. Ifthe aerial is not solid, it is preferable to provide a separating wallas at I4, which wall prevents the inner space of the aerial fromexerting any action on the tuning of the resonator proper.

In addition to the improved heat conduction furnished by thisembodiment, the arrangement is of advantage because of the convenientlocation of the cathode leads.

The reference numeral I5 indicates a plate screen which forms thehorizontal of the aerial 8. The reference numeral I2 again indicatesinsulating plates which retain the condenser plate 4 to which theelectrode 3 and the aerial 8 are attached co-axially, in rigid position.

'Ihe tubes disclosed in Figs. 5 to 8 in their fundamental constructionare comparable with those disclosed in Figs. l to 4 described above.

However, they possess I certain -mddiilcationsv which make them suitablefor use in magnetron connection.

in Figs. and 6 the reference numeral I represents the cathode, while thereference numerals I6 and I1 indicate the two halves of a so-calledcleft or split anode. The half I6 is connected to the plate 4 securedwithin the interior of the receptacle, While the half I1 is connected tothe receptacle wall 5. II there is an alternating potential between I6and I1 the result is, insofar as the frequency of this alternatingpotential approximates that of the resonator, that the condenser formedof the members 4 and 5 passes into oscillation. The short circuitcapacity of this condenser is in this embodiment as in the previouslydescribed embodiments formedv by the space between the plate 4 and thewall 6 to whichl the aerial is connected through the opening 1 in knownmanner. Insulating supports I8 retain the plate 4 in position.

It will be noted that the cathode I and the two halves I6 and I1 of thecleft or split anode are encompassed by a hood-like cylindricalconductor I9 which is conductively connected with the wall 5 and servesas a screen against the escape of loss radiation as well as the portionof the wall of the vacuum receptacle. The electrode system isencompassed by a magnetic coil 20 which produces the axial magnet eldnecessary for magnetron stimulation.

The advantage of the magnetron arrangement is that there is no grid andthat the two parts of the cleft anode have the same relative potentialrelative to the cathode. All parts of Athe arrangement thus have thevsame direct potential with the exception of the cathode which is heldat a negative potential with respect to these parts. Since the plate 4and the walls 5 and 6 have the same direct potential, the supportinsulators provided in the vicinity of the node line maybe replaced bydirect metallic supports I8, which are disposed as closely as possibleto the node line.

In Figs. 7 and 8 an embodiment is disclosed which is somewhat similar tothat disclosed in Figs. 3 and 4 but in which a magnetron connection isused and the cleft anode is comprised of more than two parts, forexample, of four parts. It is to be understood', however, that theembodiment disclosed in Figs. 5 and 6 may also be provided with a cleftanode consisting of more than two parts or halves. In Fig. 7 the cathodeI is encompassed by four parts or segments, 2|, 22, 23 and 24, of thecleft anode. This will perhaps be more apparent from Fig. 8 which is across-section on the line 8-8 of Fig. 7. The

parts 2| and '22 of the anode are in direct connection with the plate 4which is secured within the receptacle, while the parts 23 and 24 aresecured to the wall 5. The plate 4 is provided with notches orrecessesto permit the parts 23 and 24 to pass through to' the. wall 5.Anfother function of these recesses, which appear clearly in Fig. 8, isto permit the parts 23 and 24 to pass through the plate 4 with thelowest possible capacity. The short circuit capacity 4, 6, is againconnected to the margin of the resonator where the potential node lineextends, and this short circuit capacity at the same time serves as anenergy lead to the aerial 8, which extends from the horizontal. In thisembodiment, as in the embodiment previously described, all of the partswith the exception of the cathode can be maintained at the samespositivepotential relative to the cathode. It is thus possible in thisembodiment also to retain the member 4 within the resonator by means ofmetallic supports I8.

Instead of a cleft anode consisting of fou parts, the anode may becomprised o! six or eight parts whereby all of the even numbered partsare connected to the plate 4 and all uneven numbered parts to the wall 5in the same manner as shown for the four parts in Figs. '7 and 8. Themagnetic coil 20 for producing the axial magnetic field is mounted abovethe lead 25 ofthe ultrahigh frequencyl conductor.

Other electrodes can be introduced in the magnetron arrangement formodulating the load eflciency. For example, in the space between thecathode and the cleft anode a wire-shaped or otherwise formed electrodecan be provided which, through a suitable charge, will control theemission of the electrons and thereby the load on the ultra-short wavetube. It is likewise possible to dispose this control electrode outsideof the cleft anode so that it inuences the capacity emission between theindividual parts of the cleft anode.

'Ihe magnetron tube illustrated in Figs. '1 and 8 is provided with sucha control electrode for modulating emission. In this embodiment thecontrol electrode consists of metal discs 26 which are disposedperpendicular to the tube axis between the cathode and the cleft anodeand are connected to a common lead 21. electrode may be given a positiveor a negative preliminary potential. In both cases, with superposedcontrol alternating potential, a modulation of the electron flow, andconsequently of the load efliciency of the tube, can be effected.

While I have described several examples of my invention, I do not wishto be limited thereto since obviously changes can be made thereinwithout departing from the spirit of the invention.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. A vacuum discharge tube comprising a plate condenser composed of arst condenser plate and a second condenser plate, a conductor adjacentthe outer side of `said rst condenser plate and conductively connectedwith the edge of said second condenser plate, and electrodes disposedsubstantially perpendicular to said condenser plates. said secondcondenser plate and said confv ductor forming walls of a hollow body,said walls sealing said tube against radiation'losses.

K 2. A vacuum discharge tube comprising a circular plate condensercomposed of a flrstcondenser plate and a second condenser plate, acircular conductor adjacent the outer side of said ilrst condenser plateand conductively connected with the edge of the second condenser plate,the centers of said circular condenser plates and said circularconductor lying on a common axis, and electrodes in the vicinity ofIsaid axis and disposed substantially perpendicular to the condenserplates, said second condenser plate and said conductor forming walls ofa hollow body, said walls sealing said tube against radiation losses. l

3. A vacuum discharge tube as in claim 1, said electrodes forming anoscillating system having an autofrequency higher than, and aperiodicto, the autofrequency of said condenser.

Y 4. A vacuum discharge tube comprising a circular plate condensercomposed of a first condenser plate and a second condenser plate, acircular conductor adjacent the outer side of The controlsaid iirstcondenser plate and conductively connected with the edge of said secondcondenser plate, said second condenser plate and conductor forming wallsof a hollow body, said walls sealing said tube against radiation losses.said conductor forming with said rst condenser plate a short circuitcondenser, an aerial disposed co-airially with respect to said platecondenser and connected to said iirst condenser plate, and electrodes inthe vicinity of the center of the plate condenser and disposedsubstantially perpendicular to the condenser plates.

5. A vacuum discharge tube comprising a circular plate condenserconsisting of a first condenser plate and a second condenser plate, a

conductor adjacent the outer side of said ilrst condenser plate andconductively connected with the edge of said second condenser plate,electrodes disposed substantially perpendicular to said condenserplates, and vacuum-tight seals on said second condenser plate and theconductor connected therewith, both of said members combining to formthe vacuum receptacle.

6. ,A vacuum discharge tube comprising a circular plate condensercomposed of a rst condenser plate and a second condenser plate, acircular conductor adjacent the outer side of one of said condenserplates and conductively connected with the edge of the other condenserplate, said other condenser plate having a central opening therein, a.cylindrical hood-shaped conductor closing off said opening, andelectrodes disposed coaxially within said hood-shaped conductor andsubstantially perpendicular to the condenser plates.

7. A vacuum discharge tube comprising a circular plate condensercomposed of a ilrst condenser plate and a second condenser plate, acircular conductor adjacent the outer side of said first condenser plateand conductively coupled with the edge of the second condenser plate,said conductor forming with said first condenser plate a short circuitcondenser and a high frequency lead of small wave resistance, an aerialdisposed co-axially with respect to said plate condenser and connectedto said first condenser plate, said conductor having a central openingthrough which the aerial passes,` a seal of insulation material closingoi said opening vacuum tight, and electrodes in the vicinity of the axisof said circular plates and connected to said iirst and second condenserplates and substantially perpendicular thereto.

8. A vacuum discharge tube comprising 'a circular plate condensercomposed of a first condenser plate and a second condenser plate, acircular conductor adjacent the outer side of said first condenser plateand conductively coupled with the edge of the second condenser plate.said conductor forming with said rst condenser plate a short circuitcondenser and a high frequency lead of small wave resistance, an aerialdisposed co-axially with respect to said plate condenser and connectedto said iirst condenser plate, said conductor having a central openingthrough which the aerial passes, a seal of insulation material closingoi said opening vacuum tight, a

` cathode disposed co-axially with respect to the plate condenser, andleads for said cathode passing radially through said rst condenserplate.

9. A vacuum discharge tube comprising a circular plate condensercomprising a ilrst condenser plate and a second condenser plate,saldsecond plate being'provided witha central opening, a conductor adjacentthe outer side of said iirst condenser plate and conductively connectedY,

with the edge of said second condenser plate, a cylindrical hood-shapedconductor closing oi the opening in said second condenser plate andforming a solid wall electrode. a cylindrical grid dising, a conductoradjacent the outer side of saidI rst condenser plate and conductivelyconnected with the edge of said second condenser plate, and formingtherewith a metallic housing, an aerial disposed co-axially with respectto said plate condenser and connected with said iirst condenser plateand passing through a central opening in said conductor, a seal ofinsulating material closing olf said opening in a vacuumtight manner.said second condenser plate having a central opening therein, acylindricalhood-shaped electrode closing off the opening in said secondcondenser plate, said hood-shaped electrode being cov-axial with saidplate condenser, a cylindrical grid composed of axle-parallel rodsdisposed within said hood-shaped electrode and conductively connected tosaid rst condenser plate, a cathode disposed co-axially within saidgrid, insulating members at the edge of said first condenser platesupporting the same within the housing, leads to said grid and saidcathode passing through said housing at the periphery thereof, and sealsof insulating material closing oif the lead inlets into the housing in avacuumtight manner. y

11. A vacuum discharge tube comprising a circular plate condensercomposed of a iirst condenser plate and a second condenser plate, acircular conductor adjacent the outer side of said first condenser plateand conductively connected with the edge of the second condenser plate,a split anode disposed co-axially with respect to l the plate condenserand provided with a plural- -ity of segments, the even number segmentsof said anode being connected with one of the plates of the platecondenser and the uneven number segments of the anode being connected tothe other plate of said plate condenser, and a cath.

ode disposed so-axially within said split anode.

12. A vacuum discharge tube as deiined in claim 11 having metallicmembers which support one condenser plate at the edge and in potentialnodes, and a magnetic ileld coil disposed about said tube insubstantially coaxial position.

13. A vacuum discharge tube comprising a circular plate condensercomposed of a iirst condenser plate and a second condenser plate, acircular conductor adjacent the outer'side of said iirst condenser plateand conductively connected with said second condenser plate to formaimetallic housing, an aerial disposed co-axially with respect to saidconductor and connected to said first condenser plate and passingthrough an opening in said conductor, a seal of insulating materialclosing oi said opening in a vacuumtight manner, a split anode disposedco-axially within said tube and consisting of a plurality of segments,the even number segments being connected' to one of the plates of theplate conin potential nodes, leads passing through the housing at theperiphery thereof to the cathode, and a magnetic ield coil disposedsubstantially co-axial with respect to the tube.

14. A vacuum discharge tube comprising a circular plate condensercomposed o! a rst condenser plate and a second condenser plate, one ofsaid condenser plates having a co-axial opening therein, a cylindricalhood-shaped conductor closing of! said opening outwardly, electrodeswithin said hood-shaped conductor and disposed substantiallyperpendicular to said plate condenser, a circular conductorapproximately encompassing said hood-shaped conductor and the condenserplate connected therewith, said circular conductor being conductivelyconnected with the second condenser plate at its edge, an aerialconnected to said hood-shaped conductor, and a metal plate connectedwith said circular conductor and disposed perpendicularly to the axis ofthe tube.

15. A vacuum discharge tube comprising a circular plate condensercomposed of a ilrst condenser plate and a second condenser plate, saidfirst condenser plate having a co-axial opening therein, a cylindricalhood-shaped electrode closing oi said opening outwardly, a grid disposedco-axially within said hood-shaped conductor and conductively connectedwith said second condenser plate, a cathode disposed co-axially withinthe grid and passing through said second condenser plate at its axis andinsulated therefrom. a vacuum-tight seal at the entrance point of saidcathode, a lead to said cylindrical hood-shaped conductor, said leadbeing connected at the edge of said iirst condenser plate, a circularconductor approximately encompassing said hood-shaped conductor and thecondenser connected therewith, said circular conductorbeing conductivelyconnected with said second condenser plate at its edge, an aerialconnected with said hood shaped conductor, and a metal plate connectedto said circular conductor and disposed perpendicular to the axis of thetube, and insulating members at the edge of and supporting said rstcondenser plate in potential nodes against said circular conductor.

16. A device as deilned in claim 15, wherein said grid consists ofaxio-parallel rods.

17. A vacuum discharge tube comprising a circular plate condensercomposed of a ilrst condenser plate and a second condenser plate, one ofsaid condenser plates having a co-axial opening, a cylindrical hood-likeconductor closing oil said opening outwardly, a split anode consistingoi' an even number of segments and disposed within said hood-likeelectrode, the even number segments being connected with the firstcondenser plate and the odd number segments being connected with saidsecond condenser plate, a cathode disposed co-axially within said splitanode and passing through said second condenser plate from which it isinsulated, a vacuum-tight seal at the inlet point of said cathode, acircular conductor approximately encompassing said hood-like conductorand the condenser plate connected therewith, said circular conductorbeing conductively connected with said second condenser plate at theedge, an aerial connected with said hood-like conductor, and a metalplate connected to said circular conductor and disposed perpendicular tothe axis of the tube.

18. A vacuum tube as dened in claim 17, wherein said split anodeconsists oi four segments, metallic members at the edge of and mutuallysupporting the condenser plates in potential nodes. seals at thejuncture points of the circular conductor and said aerial closing oilthe interior of the tube in a vacuum-tight manner.

19. A vacuum discharge tube comprising a plate condenser consisting of afirst condenser plate and a second condenser plate, a conductorconductively connected with the edge of said second condenser plate,split anodes and a cathode disposed substantially perpendicular to saidcondenser plates, and a control electrode between the split anode "andthe cathode.

WALTER DILENBACH.

